Conventionally, in a printer such as a label printer, a thermal transfer type printer which melts an ink coated on an ink ribbon through a thermal head with heat to transfer the ink is widely used. If the ink ribbon is slack in such a printer, the printing quality deteriorates. However, due to the inertia of sending of lots of the ink ribbon a driving motor at the end time of a printing operation, slackness is likely to occur in the ink ribbon.
As a prior art, a technology relating to the thermal printer is disclosed in which by inputting a trigger signal, tension is applied to the ink ribbon by back feeding an ink ribbon supply shaft, and the slackness of the ink ribbon is thereby eliminated. On the contrary, a technology is desired in which the slackness of the ink ribbon can be eliminated automatically without inputting the trigger.